# Heat Transfer

Solve conduction-dominant heat transfer problems with convection and radiation occurring at boundaries

Address challenges with thermal management by analyzing the temperature distributions of components based on material properties, external heat sources, and internal heat generation for steady-state and transient problems.

The heat transfer equation is a parabolic partial differential equation that describes the distribution of temperature in a particular region over given time:

$\rho c\frac{\partial T}{\partial t}-\nabla \cdot \left(k\nabla T\right)=Q$

A typical programmatic workflow for solving a heat transfer problem includes these steps:

• Create a special thermal model container for a steady-state or transient thermal model.

• Define 2-D or 3-D geometry and mesh it.

• Assign thermal properties of the material, such as thermal conductivity k, specific heat c, and mass density ρ.

• Specify internal heat sources Q within the geometry.

• Specify temperatures on the boundaries or heat fluxes through the boundaries. For convective heat flux through the boundary $htc\left(T-{T}_{\infty }\right)$, specify the ambient temperature ${T}_{\infty }$ and the convective heat transfer coefficient htc. For radiative heat flux $\epsilon \sigma \left({T}^{4}-{T}_{\infty }{}^{4}\right)$, specify the ambient temperature ${T}_{\infty }$, emissivity ε, and Stefan-Boltzmann constant σ.

• Set an initial temperature or initial guess.

• Solve and plot results, such as the resulting temperatures, temperature gradients, heat fluxes, and heat rates.

• Approximate dynamic characteristics of a thermal model by using reduced order modeling (ROM).

## Functions

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 createpde Create model thermalProperties Assign thermal properties of a material for a thermal model internalHeatSource Specify internal heat source for a thermal model thermalBC Specify boundary conditions for a thermal model thermalIC Set initial conditions or initial guess for a thermal model solve Solve heat transfer, structural analysis, or electromagnetic analysis problem assembleFEMatrices Assemble finite element matrices reduce Reduce structural or thermal model reconstructSolution Recover full-model transient solution from reduced-order model (ROM) linearize Linearize structural or thermal model linearizeInput Specify inputs to linearized model linearizeOutput Specify outputs of linearized model
 interpolateTemperature Interpolate temperature in a thermal result at arbitrary spatial locations evaluateTemperatureGradient Evaluate temperature gradient of a thermal solution at arbitrary spatial locations evaluateHeatFlux Evaluate heat flux of a thermal solution at nodal or arbitrary spatial locations evaluateHeatRate Evaluate integrated heat flow rate normal to specified boundary
 pdeplot Plot solution or mesh for 2-D problem pdeplot3D Plot solution or surface mesh for 3-D problem pdegplot Plot PDE geometry pdemesh Plot PDE mesh pdeviz Create and plot PDE visualization object
 findThermalProperties Find thermal material properties assigned to a geometric region findHeatSource Find heat source assigned to a geometric region findThermalBC Find thermal boundary conditions assigned to a geometric region findThermalIC Find thermal initial conditions assigned to a geometric region

## Objects

 ThermalModel Thermal model object ReducedThermalModel Reduced-order thermal model SteadyStateThermalResults Steady-state thermal solution and derived quantities TransientThermalResults Transient thermal solution and derived quantities ModalThermalResults Modal thermal solution

## Properties

 ThermalMaterialAssignment Properties Thermal material properties assignments HeatSourceAssignment Properties Heat source assignments ThermalBC Properties Boundary condition for thermal model NodalThermalICs Properties Initial temperature at mesh nodes GeometricThermalICs Properties Initial temperature over a region or region boundary PDESolverOptions Properties Algorithm options for solvers PDEVisualization Properties PDE visualization of mesh and nodal results